Carbon-Based Catalysts for Selective Electrochemical Nitrogen-to-Ammonia Conversion

Abstract

Electrochemical nitrogen reduction reaction (NRR) to ammonia (NH 3 ) driven by renewable electricity is a promising alternative to the current energy-intensive and fossil feedstock-dependent Haber−Bosch (H−B) process. The intrinsic inertness of N 2 molecule and competition of hydrogen evolution reaction (HER) are the primary challenges for NRR. Although transition metal-based electrocatalysts can solve the kinetic limitation of NN activation through the π-back-donation process, the d-orbital electrons of transition metal atoms facilitate the formation of a metal-H bond, boosting the undesirable HER. Carbon-based materials featuring tunable electronic structures and facile formation of defects have significantly improved electrocatalytic NRR activity in the past few years. Therefore, a review on state-of-the-art carbon-based catalysts for NRR is timely to provide a summary of recent developments in theoretical and experimental aspects. In this review, various defect engineering strategies for the evolution of the desired carbon-based electrocatalysts are comprehensively summarized. The intrinsic relationships between the structures of the defective carbon materials and NRR performance are also discussed in detail. This review aims to stimulate greater interests for developing more efficient electrocatalysts for NRR in the future.

Creating Hybrid Coordination Environment in Fe‐Based Single Atom Catalyst for Efficient Oxygen Reduction

“…To address this limitation, constructing single atom catalysts (SACs) on these carbon materials comes under the spotlight. Such isolated metal atoms, coordinated with heteroatom in carbon, simultaneously share the advantages of heterogeneous and homogeneous catalysts [4b,6] . SACs based on nitrogen‐doped carbon consisting of Fe−N 4 active sites (planar structure of a Fe atom coordinated by four N atoms) remain the most promising option for ORR.…”

Catalytic Kinetics Regulation for Enhanced Electrochemical Nitrogen Oxidation by Ru‐Nanoclusters‐Coupled Mn3O4 Catalysts Decorated with Atomically Dispersed Ru Atoms

“…Commercial nitric acid is produced through a two-step procedure including artificial ammonia synthesis and the following catalytic oxidation. [5][6][7][8] NH 3 is usually produced from the Haber-Bosch process, which involves the reaction with H 2 and N 2 under high temperature (400-500 °C) and high pressure (200-300 atm) conditions. [9][10][11][12] HNO 3 is then obtained through NH 3 oxidation (Ostwald process) under harsh reaction conditions (400-600 °C, 150-250 atm).…”

Strategies to activate inert nitrogen molecules for efficient ammonia electrosynthesis: current status, challenges, and perspectives

“…Non-metal doping is the primary approach for boosting the NRR activity of electrocatalysts, particularly for metal-free carbon materials, which are prevalently employed in the NRR field at present. 68,69 This strategy can effectively induce electron-deficient sites via the electrontransfer process between carbon and heteroatoms. Furthermore, the resulting electron-deficient sites can be either carbon atoms themselves or heteroatoms, which depends on the difference in the electronegativity values between carbon and the heteroatom.…”